Early‐Stage Phenotypic Variation, Repeatability and Multivariate Profiling of Macauba ( Acrocomia spp. ) Hybrids

Macauba ( Acrocomia spp.) is an underutilised palm, native to Brazil and other tropical regions of the Americas, with substantial potential for vegetable oil and bioenergy production. However, its long juvenile phase delays the identification of promising parents and hybrid combinations. This study characterised the early vegetative performance of 60 individual macauba hybrids derived from intraspecific Acrocomia aculeata crosses and an interspecific A. aculeata × Acrocomia totai cross. Seventeen traits related to plant architecture, leaf morphology and biomass were evaluated over 2 years (2023–2024) using a mixed model fitted by restricted maximum likelihood, with the year as a fixed effect and accession as a random effect. Repeatability, predicted accession effects, trait correlations, principal component analysis, hierarchical clustering and a composite vigour index were also examined. Considerable phenotypic and persistent among‐plant variation was observed, where the number of fallen leaves showed the highest phenotypic and among‐plant coefficients of variation (78.2% and 55.9%, respectively). Repeatability was moderate for all traits ( R = 0.42–0.52), except central pinna width ( R = 0.11). Fresh mass of pinnae was strongly correlated with dry mass of pinnae ( r = 0.90) and moderately correlated with other vegetative and biomass‐related traits, including central pinna length ( r = 0.67), indicating that fresh pinna mass may serve as a practical proxy for pinna dry mass. The first two principal components explained 61.9% of the multivariate variation, driven mainly by biomass and structural traits. The vigour index identified 10 putative hybrid candidates, with H19‐14, H20‐5 and H17‐9 receiving the highest scores. These outcomes provide useful phenotypic information for early screening in macauba, although the selected plants require further validation through replicated, multiyear evaluations that include fruit and oil‐production traits. This work offers a practical starting point for accelerating early‐stage selection in macauba breeding to enhance its productivity as a sustainable bioenergy crop.